Well, actually it's not strange, but as to be expected:
old situation:
- type username
- wait awhile
- send tab-key and a password and enter-key all at once
== no time for processing
new situation:
- type username and leave field to trigger processing
- allow other processing to run by giving a time-slice back to the system by using sleep
- send password and enter-key so second field can be processed and login handled
== timing is no issue as all processing is allowed when required by the system
voila